A main requirement of circuits working at radio-frequencies is linearity. Linearity of low-noise amplifiers is typically characterized by special parameters commonly indicated with the acronyms IIP3 and OIP3, respectively the input and output “third order intercept points”, that measure the intermodulation distortion (IM3) introduced by the amplifiers.
Classic measuring instruments allow estimating the parameter OIP3, the maximum value of which is limited by nonlinearities introduced by the instruments. Therefore, measurements carried out on highly linear circuits are carried out with great care. The meaning of the parameters IIP3, IM3 and OIP3, that characterize intermodulation distortions, are briefly illustrated hereinbelow for better understanding the field of the invention.